The nosewheel right inboard roller bearing failed. It is likely that the lack of lubrication as a result of the grease dam being dislodged from its normal position was a contributing factor. The friction temperatures created by the failed roller bearing exceeded the cadmium melting point. Cadmium penetrated and weakened the intergranular structure of the nose landing gear axle, causing it to fail due to liquid metal embrittlement.Findings as to Causes and Contributing Factors The nosewheel right inboard roller bearing failed. It is likely that the lack of lubrication as a result of the grease dam being dislodged from its normal position was a contributing factor. The friction temperatures created by the failed roller bearing exceeded the cadmium melting point. Cadmium penetrated and weakened the intergranular structure of the nose landing gear axle, causing it to fail due to liquid metal embrittlement. The dislodged inner-bearing grease dam allowed grease to migrate from the inboard roller bearing of the right nosewheel to the inside of the nosewheel assembly. A reduction in lubrication increases the cage loads and may lead to bearing failures.Finding as to Risk The dislodged inner-bearing grease dam allowed grease to migrate from the inboard roller bearing of the right nosewheel to the inside of the nosewheel assembly. A reduction in lubrication increases the cage loads and may lead to bearing failures. Safety Action Safety Action Taken Air Canada has taken steps to have the axles for its nose landing gears coated with SermeTel to reduce the likelihood of axle failures from cadmium infusion as a result of high friction heat generated from bearing failures. SermeTel is an anti-corrosive and chemical-resistant base applied as an initial coating prior to decorative coatings of epoxy resin and polyurethane paints. It is an inorganic formula, consisting of an aqueous carrier containing a mixture of magnesium chromate, phosphates and silicates, and aluminum powder. Air Canada has also issued a maintenance alert and revised its wheel installation job card to stress the importance of a wheel inspection prior to installation and to ensure the recommended wheel installation tools and torques are used in accordance with the Aircraft Maintenance Manual. The Air Canada wheel shop manuals were revised to raise the awareness of the importance of grease dams and seal installations. In May 2004, Goodrich released Service Letter1991 that recommends MobilSHC-100 grease for the wheel bearings due to its superior adhesion properties, which also increase corrosion protection and bearing lubrication. Goodrich also issued Service Bulletin3-1531-32-3 in July2004, with new inspection procedures for bearing grease seals on AirbusA318, A319,A320and A321aircraft. Airbus has designed an integrated retaining ring and seal that is being tested for qualification purposes. Testing includes roll and landing tests under different loads, as well as high-pressure water tests to demonstrate the enhanced performance of the new design in protecting the seal and bearing from external contaminants.